Patent Application
20170266020
A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever.
The present invention relates to a novel design for a mechanical hand that introduces a new level of tactile operation for those who need such prosthetic devices. It is adapted to matingly connect with various standardized prosthetic hand/arm components, thereby allowing a simple conversion for existing prosthetic hand users.
Despite the portrayal of high tech prosthetic hands as the norm on the media, the current state of the art for prosthetic hands/arms for the average person leaves much to be desired. The most widely used terminal device is known as the “Hosmer™ Hook” and has been around since 1912. The basic Hosmer™ Hook has a single pair of opposable, crescent shaped pinchers. It is a voluntary-open terminal device having a series of elastic bands that keep the pinchers closed. It is body-powered, very reliable, predictable, waterproof, affordable and enables precise grasping of small objects with good visibility of item being grasped. It is very robust and capable of manipulations with very small items. Unfortunately, it has several drawbacks. It is somewhat menacing to look at, visually intimidating to third parties, has a limited ability to grasp irregularly shaped or large objects, does not lend itself to disguise with garment cover. While this device performs a single pinching task well, it is limited to manipulations from rigid, non-adjustable, fixed length pinchers rotating in a single plane.
Other more sophisticated (e.g. robotic) hands are capable of performing with more dexterity but are also limited in many ways. These five-fingered robotic hands tend to feature complex electo-mechanical assemblies and as such tend to be expensive, fragile and require a silicone glove to be waterproof. They are non flexible, non customizable and frequently incorporate motors or other electrical systems within the hand itself resulting in a stiff monolithic palm which is not scalable and not lifelike. Performance of these hands is limited by battery life. Many of such prosthetic hands are not scalable or available in small sizes for children or women.
Henceforth, an aesthetically appealing, body-powered, five-fingered, prosthetic hand, would fulfill a long felt need in the prosthetic device industry. Similarly, a scalable prosthetic hand that resembled a human hand would allow for a greater visual and emotional acceptance. This new invention utilizes and combines known and new technologies in a unique and novel configuration to overcome the aforementioned problems and accomplish this.
In accordance with the invention, the object of the present invention, which will be described subsequently in greater detail, is to provide an improved mechanical hand that is able to connect to the existing body powered harness or a myoelectric controlled systems.
It is another object of the present invention to provide a prosthetic hand that approximates the look and function of the human hand with five digits capable of being manipulated with an opposable thumb capable of adjustable angle opposability.
It is yet another object of the present invention to make a human hand-like prosthetic device wherein each digit is made from a series of different sized connected elements so as to allow scalability of the device.
It is still another object of the present invention to provide a lightweight prosthetic hand that can be fabricated from the assembly of a minimal number of components, many identical, each of which can be economically and simply fabricated.
It is a further object of the present invention to provide a prosthetic hand with the capacity for individual digit control.
It is still another object of the present invention to offer a prosthetic hand that has set of digits that incorporate metacarpal members which pivot at their proximal end in a plane that resides approximately 90 degrees relative to the plane of curl or extension of the digits.
It is a final object of the present invention to offer an improved, robust prosthetic hand capable of providing an entire host of different grasping and holding features configured similar to a human hand so as to present a five digit crushable compliant grasping profile that is able to be powered/operated by a industry standard body powered harness.
The improved mechanical/prosthetic hand has many of the advantages mentioned heretofore and many novel features that result in a new human hand-like device which is not anticipated, rendered obvious, suggested, or even implied by any of the prior art, either alone or in any combination thereof.
The subject matter of the present invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. However, both the organization and method of operation, together with further advantages and objects thereof, may best be understood by reference to the following description taken in connection with accompanying drawings wherein like reference characters refer to like elements. Other objects, features and aspects of the present invention are discussed in greater detail below.
Note: Only
The above description will enable any person skilled in the art to make and use this invention. It also sets forth the best modes for carrying out this invention. There are numerous variations and modifications thereof that will also remain readily apparent to others skilled in the art, now that the general principles of the present invention have been disclosed.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims appended hereto.
In this respect, before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. As an exemplar, the number of digits and type of digit and scalable size of each digit is fully customizable for both prosthetic and robotic applications. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting.
As used herein, the term “mechanical hand” or “prosthetic hand” refers to a device often referred to as a prosthetic arm or prosthetic arm. Although discussed herein used as a prosthetic hand, it is known that it may be used in robotics applications or other powered applications as well because of its human hand-like tactile similarities.
The term “crushable” refers to the ability to have the digits of the mechanical hand simultaneously pivot at their proximal connections to the palmer plate and also simultaneously flex slightly about their polymer spacers when external forces are applied. In this manner the digits may be forced together or undergo individual shocks without damage to the hand.
It is to be noted, that because of the similarities between the prosthetic hand and the human hand, much of the medical terminology of the human hand has been adopted for the designations of the various elements of the device.
The improved prosthetic hand 2 has been modeled after the human form with five scalable digits. Each digit is separately capable of dorsal extension (finger opening) and palmer flexion (finger closing) and with the ability to be individually controlled as desired.
Looking at
The palmer plate 8 is the central hub or means for operationally supporting all of the digits or digital movements. It also mounts to the wrist for operational connection to the user.
The hand 2 is designed to be a terminal device wherein it is affixed to a standard prosthetic socket that mounts to the distal end of the user's residual limb. Generally, a socket is fitted on the residual limb and connects the residual limb to the prosthetic device 2. These sockets are attached by a tight, custom friction or vacuum fit over the residual limb. The connection of the prosthetic hand 2 to the residual limb is not discussed herein. There are several different matingly engageable mechanical configurations that may be utilized, each of which is commercially available. Adaption of the prosthetic hand to any of these devices is merely an act of mechanical manipulation as would be well known by one skilled in the art.
Operation of the prosthetic hand may be via one of the common cable and sling arrangements that are typically worn up the arm and across the shoulders of the user (body powered). Optionally, the prosthetic hand 2 may be operated by motorized driven myoelectric control initiated by a signal. Such signals may come from an electrical impulse generated by an electrode operationally contacting a muscle group. (e.g. in the forearm) It is to be noted that when used as a human prosthetic device, the hand 2 is designed to be crushable, having flexible spacers 14 between all digits along the width of the hand 2, as well as pivotal connections at the base of each finger digit 4 and the thumb digit 6. These flexible spacers 14 in the preferred embodiment are simply flexible cables sheathed with a pliable polymer between the sections spanning adjacent digits. There are flexible spacers 14 spanning between adjacent digits between the pinky digit 34 and index digit 28. There is another one spanning between the index digit 28 and the thumb digit 6. (Although there may be more of less flexible spacers 14 to accomplish the same functionality of the hand 2.) This synergistic design allows for the “crushable” feature of the hand 2 and prevents irreparable harm to the hand or its components under unexpected mechanical loads or shock. Additionally, the flexible spacers 14 between all digits along the width of the hand 2, allows simultaneous limited motion of some or all of the digits with respect to the other digits.
The prosthetic hand 2 has numerous physical configurations so that it can be individually customized for each user or for specific tasks that the user may be attempting. One such example can be seen in
Looking at
From the thumb digit outward the digits are index 28, middle 30, ring 32 and pinky 34 (see
Looking at
The finger digit's metacarpals 24 and the thumb digit's axially adjustable metacarpal 26 have a similar but slightly different structure than the phalanges, although still based on the tube section design. In
The thumb digit metacarpal's structure as shown in
The proximal end of the distal phalange 18 is connected to the distal end of the middle phalange 20, and the proximal end of the middle phalange 20 is connected to the distal end of the proximal phalange 22, and the proximal end of the proximal phalange is connected to the distal end of metacarpal 24 or 26 in the identical manner outlined above to facilitate the linear assembly of the digits (finger 4 or thumb 6). In the case of the thumb digit 6, the middle phalange 20 is eliminated and the distal phalange's proximal end is connected to the distal end of the proximal phalange 22. The assembly of the individual phalange-phalange connections, and phalange-metacarpal connections of the finger digits and thumb digit, are best explained in
Beginning with a distal phalange 18, the two coupling flanges 41 at the proximal end 48 of the tube section are fitted adjacent (on top or below) of the two coupling flanges 41 at the distal end 46 of the middle phalange 20 such that their pivot pin orifices 40 align. Through one set of aligned pivot pin orifices 40 is inserted a first pivot pin 60. The pivot pin 60 is less than one half of the width distance between the parallel connection flanges 41 of a tube section 38. Each pivot pin 60 has a head that resides normally to a shaft section that has an axial groove 64 formed therein, sized to accept a circular retaining clip 62. These are commercially available mechanical fasteners, well known in the art. A retaining clip 62 is placed in the axial groove 64 in the pivot pin 60 such that the inner face of the retaining clip 62 resides adjacent to the inner face of the distal end 46 of the middle phalange 20. A torsion (wound) spring 66 is placed over the shaft section of the pivot pin such that its two spring legs 68 (that reside 180 degrees apart and at opposite ends of the spring body) are constrained by the inner wall of the tube sections 38 of the connected phalanges and or metacarpals. (These spring legs 68 are long enough to extend into the internal cavity of the tube section 38.) A spring cover 70 is placed over the spring 66 and the underlying shaft section of the first pivot pin shaft section, and a second pivot pin 60 is installed and affixed through the second set of aligned pivot pin orifices 40 in the distal phalange's proximal end 48 and the middle phalange's distal end 46 in an identical fashion as described above. The spring cover 70 merely prevents the cable 72 from interfering with the spring 66. It is to be noted that the spring 66 may be oriented such that the torsional spring legs 68 may either open or close the joint. The closing order of individual phlanges is determined by the strength of the respective wound springs selected for use in that specific phlange. Generally the strength of the wound spring decreases toward the distal end of the digits.
Looking at
The remaining connections of the phalanges and metacarpals of digits 4 and 6 are similarly made. The cable 72 is routed through cable guides 42 traversing the linear arrangement of phalanges and metacarpals, passing through the internal cavity of each tube section 38 and the consecutive cable slots 44. The distal end of cable 72 is affixed to the distal end of each distal phalange 18.
It is to be noted that the cable system used to operate the digits may be of two different configurations. The first configuration (preferred embodiment) uses two cables 72, one internally traversing the dorsal side and one individually traversing the palmer side of the digit, each running over the palmer plate 8 and operably connected at its proximal end to the user's preferred control system. (e.g. body-powered or myoelectric) The second configuration utilizes but one cable routed through either the palmer or dorsal side of the digits and similarly operationally connected as above. Where only one cable 72 is provided, the springs 66 serve to return the digits to the open or closed position depending on whether the cable runs on the palmer side and closes the digit or the dorsal side and opens the digit. (In this way the hand 2 can be configured to operate in either the voluntary open or voluntary closed modes.)
The stiffness of the springs 66 are set for differing tensions across the various phalanges (each phalange relative to the adjacent phalange) so as to control the closing profile of the entire hand similar to that of the human form or as desired. Generally, the spring 66 is set to open (extend) the finger at the joints with the weakest spring tension (stiffness) at the distal end of the distal phalange and increasing gradually toward the proximal end of the proximal phalange.
Looking at a voluntary-close configuration, the cable 72 on the palmar side of the digits under tension actively draw the digits inward in flexion. Since each joint is held extended by differing spring tensions, when the cable 72 is tensioned, the digits curl inward first from the distal end in a human-like fashion where the joints with the weaker spring forces begin to curl inward first. All joints passively spring open when the palmer cable tension is relieved.
If a single-cable, voluntary-open (cable tension to open) system is employed, the cable on the dorsal side of the digits under tension draw the digits outward in extension and the springs 66 serve to close the digits in flexion.
If a single cable voluntary-close (cable tension to close) system is employed, the cable on the palmar side of the digits under tension draw the digits inward in flexion and the springs 66 serve to extend the digits.
In a dual cable system, the tension of either cable actively controls both the flexion or extension of the digits. Wherein there is no or reduced dorsal cable tension, the springs 66 again act to control either the opening or closing profile of the digits.
On the palmar plate 8 there is also a central orifice 86 that allows the connection of the wrist top bracket 90 and the thumb rotation plate 10. The thumb rotation plate 10 (
Between the parallel hinge arms 88 of the thumb rotation plate 10 is pivotally affixed the thumb pivot flange 12. This pivot flange 12 has a pair of parallel ears 95 that are substantially similar to the hinge arms 88. The ears 95 are located atop each of the hinge arms 88 and at least one thumb pivot pin 96 inserted therethrough. This may be accomplished in a fashion similar to that of the digit joints as outlined herein.
There is a torsion coil spring 102 around the thumb pivot pin 96 that functions to apply rotational torque between the thumb rotation plate 10 and the thumb pivot flange 12 so as to keep the thumb digit 6 in an open position relative to the palmer plate 8. This ensures that as the user approaches an object to manipulate, the thumb is not initially in the way of the operation. This gives a maximally open position for grasping.
The wrist top bracket 90 (
The mechanical hand as disclosed herein, has been discussed in association with uses as a prosthetic hand although use in the robotics industry is anticipated with a series of operable servo motors controlling the various digits. It is envisioned that the control of the individual digits through the servo motors may be manipulated by a device affixed to the hand of the operator so as to mirror their digit movements.
From the disclosure it can be seen that the present invention prosthetic hand has a plethora of capabilities not previously provided in the prior art prosthetic hands. It is both scalable and scalable proportionately because each of the segments of the digits, the palmer plate, the thumb pivot plate and the wrist are individually sizeable, likewise all components of the prosthetic hand distal of the wrist are similarly scalable. This allows for individual customization of geometric configurations tailored to specific use patterns (ie longer fingers wherever needed. The prosthetic hand can work powered by the body (manual) or a motive source (electricity, hydraulics etc) under myoelectric signal operation. The hand is crushable since it is capable of having flexible and pivotable connections between rigid members along the length and width of the hand. It is waterproof having a lack of sensitive electronics. It has a strong lightweight design due to the hollow tubular member design. It is modular wherein individual parts can be replaced for quick repair. It can perform multiple tasks because of its individually adjustable, controlable finger digits. From an aesthetics point, it is visually pleasing able to be offered in colors and textured gripable soft resilient digit sleeves. The hand can be operated in the voluntary-open or voluntary-closed position by simply installing the springs in the digits in a reverse manner. It will deform before failing thereby giving indication of overload before failure. Its body powered version will be “plug and play” into the existing prior art sockets allowing patients to have the option of switching out prosthetic hands and not having to relearn how to work their cable harness again. It offers excellent visibility of objects grasped due to the separation of finger digits and the voided areas of the palm and digits. Finally, the hollow digit structure allows for ample room to add future internal components from emerging technology.
Those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
